Fish have a lateral line running along each side of their bodies. Each line is a small canal extended along the length of a side of the fish. The canal is filled with a thick liquid. Numerous pores along the length of the canal are open to the outside in the skin or between the fish scales. Nerve endings joined to the canal are part of the nervous system of the fish. The lateral lines allow the fish to monitor information about its surroundings. The fish senses the changes in current, temperature, pressure and direction of the water flow. The lateral lines also function to monitor balance and operate as a sonar system. As the fish swims, it produces motion that sends out vibrations that are reflected off of objects. The reflected vibrations or signals are picked up by the sensitive lateral lines. The nerve endings sense the signals picked up by the lateral lines and transmit the signals to the nervous and control/command systems of the fish. It has been observed that fish respond to sound by swimming to the source of the sound vibrations.
A fishing lure that utilizes sound to attract fish is described by Lowes, Jr. in U.S. Pat. No. 3,397,478. The Lowes fishing device produces pulse vibrations as it is drawn through the water. These vibrations are produced by a pair of bladed rotatable members mounted on a single shaft. A helical cam interposed between the rotatable members causes forward and reverse movements of one rotatable member to produce intermittent sounds. An audible fishing lure for producing chirping and clicking sounds to attract fish is disclosed by Tay in U.S. Pat. No. 3,112,576. The Tay lure has a pair of oppositely pitched spinners rotatably mounted on a single rigid shaft attached to a fish line. The spinners strike each other during their rotation to produce clicking sounds.